ASP.NET Core反射图

Question

I did settings for RabbitMQ, for example my extension:

public static class QueueExtension
{
    public static IServiceCollection UseQueue<TQueue, TApiService>(this IServiceCollection services, string host, string login,
        string password, string queue, IDictionary<string, object> arg) where TQueue : class, IEventHandler where TApiService : class, IService
    {
        if (services == null)
            throw new ArgumentNullException("services");
        return UseQueue<TQueue, TApiService>(services, typeof(TQueue), typeof(TApiService), host, login, password, queue, arg);
    }

    public static IServiceCollection UseQueue<T, Y>(this IServiceCollection services, Type queueType, Type apiServiceType, string host, string login,
        string password, string queue, IDictionary<string, object> arg) where T : IEventHandler where Y: IService
    {
        if (services == null)
            throw new ArgumentNullException("services");
        if (queueType == null)
            throw new ArgumentNullException("queueType");
        if (apiServiceType == null)
            throw new ArgumentNullException("apiServiceType");

        var parametersQueueType = queueType
            .GetConstructors()
            .SelectMany(p=>p.GetParameters())
            .Select(p=>p.ParameterType)
            .ToList();

       var parametersType = services
            .Where(p => parametersQueueType.Select(z => z.FullName)
            .Contains(p.ServiceType.FullName))
            .ToList();

       var parameters = new List<object>();

       parametersType.ForEach(p =>
       {
           parameters.Add((Y)Activator.CreateInstance(p.ImplementationType));
       });

        var impl = (T)Activator.CreateInstance(queueType, parameters);

        var queueService = new QueueServiceImpl(host, login, password, queue, arg);
        queueService.ReceivedMessage += (sender, ea) =>
        {
            var body = ea.Body;
            var message = Encoding.UTF8.GetString(body);
            impl.MessageHandler(message);
        };
        queueService.Start();

        return services;
    }

}

I use it in startup.cs :

services.UseQueue<PrimaryEventHandlerImpl, IRsmService(
    Configuration[AppConstants.HostPrimary],   
    Configuration[AppConstants.LoginPrimary],
    Configuration[AppConstants.PasswordPrimary],
    Configuration[AppConstants.QueuePrimary], 
    arg
);

But it wrong in all time do error in this line:

 var impl = (T)Activator.CreateInstance(queueType, parameters);

Say that:

Constructor ontype Monq.Core.Service.RSMModeGenerator.Services.PrimaryEventHandlerImpl not found.

but this my PrimaryEventHandlerImpl.cs :

public class PrimaryEventHandlerImpl : IEventHandler
{
    private IRsmService _rsmService;

    public PrimaryEventHandlerImpl()
    {

    }
    public PrimaryEventHandlerImpl(IRsmService rsmService)
    {
        _rsmService = rsmService;
    }
    public void MessageHandler(string json)
    {
        var events = JsonExtensions.JsonToObject<Event>(json);
        if (events.Priority != 5)
        {
            //var services = _rsmService.GetServices();

        }
    }
}

What I want to do make it work correctly?

Answer 1

Change

var impl = (T)Activator.CreateInstance(queueType, parameters);

to

var impl = (T)Activator.CreateInstance(queueType, parameters.ToArray());

Answer 2

What u are trying to do resolves in much simple and flexible way.

static IServiceCollection UseQueue<T>(this IServiceCollection services, 
                                      RabbitMQOptions options) 
        where T : class, IEventHandler
    {
        if (services == null)
            throw new ArgumentNullException("services");
        if (options == null)
            throw new ArgumentNullException("options");

        services.AddTransient<T>();
        services.AddTransient<IQueueService, QueueServiceImpl>();
        services.AddSingleton<RabbitMQOptions>(sp => { return options; });

        var serviceProvider = services.BuildServiceProvider();

        var rabbitImpl = serviceProvider.GetService<T>();
        var queueService = serviceProvider.GetService<IQueueService>();

        queueService.ReceivedMessage += async (sender, ea) =>
        {
            var body = ea.Body;
            var message = Encoding.UTF8.GetString(body);
            await rabbitImpl.MessageHandler(message);
            queueService.Channel.BasicAck(ea.DeliveryTag, false);
        };
        queueService.Start();

        return services;
    }